Warming up for sleep? Ground squirrels sleep during arousals from hibernation

Neurosci Lett. 1991 Jul 22;128(2):265-8. doi: 10.1016/0304-3940(91)90276-y.


Hypothermia during mammalian hibernation is periodically interrupted by arousals to euthermy, the function of which is unknown. We report that arctic ground squirrels (Spermophilus parryii) consistently sleep during these arousals, and that their EEG shows the decrease in slow wave activity (delta power) that is characteristic of a declining requirement for sleep. These results are consistent with the novel hypothesis that the need for sleep slowly accumulates during torpor, and that returning to euthermy is periodically required to allow sleep. Sleep thus seems to be energetically expensive for a hibernating mammal, and cannot be considered solely a strategy for saving energy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Arousal / physiology*
  • Body Temperature / physiology*
  • Electroencephalography
  • Electromyography
  • Hibernation / physiology*
  • Sciuridae / physiology*
  • Sleep / physiology*
  • Sleep, REM / physiology